Tumbling-star



(No Model.)

G. D. BARTLETT. TUMBLING STAR.

No. 591,225. Patented 001;. 5,1897.

' UNITED TATES PATENT oF aca-yyi 'cnoReE =1). BARTLETT, or Pl.Yl\I0UTI'I," Mnssnc nvsn'rrs.

IUM BuNe-s Aaf 1 SPECIFICATION forming part of Letters Patent No. 591,225, dated'october, 1897.

Application tiled January 11, 1896. Serial No. 575.073. I (No mqdolr) To all whom it may concern.-

Be it known that I, GEORGE D. BARTLETT, of Plymouth,Plymouth county, in the State of Massachusetts, have invented a certain new and useful Improvement in Tumbling-Stars, of which the following is a specification.

The invention relates to means for cleaning small castings bytumblin g ina revolving case or box to remove the adhering material composed of molding earth more or less baked by the intense heat to which it has been subjected when the iron was in a melted state. It is common to tumble the castings with a quantity of loose pieces technically known as tumbling-stars, and the castings are more rapidly and thoroughly cleaned 'by reason of the action of these added pieces on the surfaces. It is important thatthe tumbling-stars shall be hard and of such form that they will act in all the reenterin g angles of the castings.

I make the tumbling-stars of sheet metal, high steel, about N 0. 16, Birmingham gage.

I cut the sheets into small square pieces and stamp them into dishing form, crimp, and harden them.

The accompanying drawings form a part of this specification and represent what I consider the best means of carrying out the invention.

Figure 1 is a view of the full side of one of my tumbling-stars. line 2 2 in Fig. 1. Fig. 3 is a view of the hollow side, and Fig. 4. is a section on the line 4 4 in Fig. 1. Fig. 5 is a section corresponding to Fig. 2, but showing. the same tumblingstar afterit has been much worn. Fig. 6 is a view corresponding to Fig. 3, showing the star in the same worn condition. Fig. 7 shows the blank before it is treated in the dies. The dotted lines thereon indicate the skewed position of the indentations produced by the dies in theact of stamping. I

Similar letters of reference indicate corresponding parts in all the figures where they appear. I I

I roll plates of high steel down to a thickness of abont'a sixteenth of an inch and, havin g them properly heated-,cut them into square blanks and stamp them each into a star form,

as indicated in the figures.

Fig. 2 is a section on the A is the body of the metal, and A the points which were the corners of the original square blanks. I

A are recesses produced by crimping, deflecting, or dishing the metal strongly midway between each point and the next. The form may be induced by"comprcssing the sheet metal in a'heated state between two dies of the required form. The blanks are set a little askew relatively to the dies, and the eifect is to bend the'metal slightlyfhookwise at the several points, so as to give increased sharpness, as indicated by A Thislforni gives superior action to the several points while the stars are new.- I will designate by B B the cross-marks produced by the action of the dies in the hollow sides. I My sheet-metal tumbling-stars thus produced, dished and made angular, may be hardened at the same heat, as the shaping is offected by simply dropping them from the dies into cold water. They may, if preferred, be separately heated and plunged into' water which has been doctored with salt or other material to get the highest degree of hardness. A liberal quantity of these stars are placed in the tumbling-barrel with the castings to be cleaned, and as the work proceeds their thin edges are presented irregularly to all parts of the castings the same as the ordinary tumbling-stars, but the fact that they are of sheetsteel, treated as described, gives them superior hardness, so that agiven quantity of my stars will serve for a long period without appreciable wear. The form gives the quality that they continue to present eifective working edges after they have been much worn.

The sheet-metal stars, unlike the castings ordinarily used for this purpose, present the same thickness at their edges after they have been worn away to a quarteroranyoflrer fraction of their original sizes.

By making my tumbling-stars from sheet metal of the form shown I am enabled to use all thematerial and to cut it to the required angular shape with ordinary tools and labor.

My improved tumbling-stars may be used in all respects in the ordinary manner. I can use the ordinary means, as screening or winnowing, to separatemy stars from the castings and from the more or less pulverized scale which the tumbling operation has removed. v

Instead of using. high steel I can use soft steel or simply iron as the material for my sheet metal, and after the pieces have been cut and pressed, which may with such material he done cold, I can carbonize the surfaces or by sufficiently long treatment in the retort can carbonize the sheet metal quite through,

in suchcases preferably hardening by the heat used to carbonize.

I claim as my invention 1. As an improved article of manufacture, a freely-tumbling-star composed of an angula'r piece of sheet-steel, dished, crimped and hardened, and externally presenting the radial angular edges substantially as herein specified.

2. In a tumbling-star, an angular piece of sheet-steel dished, having its several points bent hookwise as indicated by A the whole star hardened, as herein specified. v

In testimony that I claim the invention above set forth I affix my signature in presence of two witnesses.

' v I GEO. D. BARTLETT.

Witnesses:

FLORA L. BARTLETT, FRED BARTLETT. 

